Microreaction
Technology
On the other hand, microreaction technology
is an effective tool for process intensification and
hazard control. Owing to the dimensions in the micrometer
range, this technology brings some benefits that are
broadly accepted. They exhibit advantageously
high surface-to-volume ratios and short retention times
of the reactants and they enable continuous
and very precise control of the reaction scenario.
The high surface-to-volume ratio in microreactors gives
them far better heat exchange characteristics than attainable
in macroscopic batch or flow-through reactors.
The microreaction technology is very interesting for
mixing sensitive reactions. By increasing mixing quality
and eliminating hot spots, unwanted side, subsequent
and decomposition reactions can be suppressed.
Especially when fast and highly exothermic reactions
are considered that provide a broad spectrum of by-products,
significant benefits will be obtained. Beside other
reactions, the table below demonstrates the increase
of yield for two different nitration reactions by using
microreaction technology. Though the increase of yield
varies for the different examples, it is obvious that
in any case microreaction technology provides
significant process intensification compared to conventional,
macroscopic batch processes.
examples for process intensification using microreaction
technology (laboratory scale)
| |
yield
[%] |
increase
of |
| reaction |
batch |
microreactor |
yield
[%] |
| Friedel-Crafts
monoalkylation 1 [1] |
37 |
92 |
+
55 |
| Friedel-Crafts
monoalkylation 2 [1] |
14 |
84 |
+
70 |
| Grignard
Reaction [2] |
49 |
78 |
+
29 |
| toluene
nitration to para-nitrotoluene [3] |
33 |
44 |
+
11 |
| double
nitration of dialkylurea [4] |
10 |
85 |
+
75 |
|